Cupola and like furnace



J. E. FLETCHER CUPOLA AND LIKEFURNACE April 1.2, 1932.

' Fig.2

Original Filed May 19, 1930 I I 'lNVeMTmQ mm venient manner.

Patented Apr. 12, i932 'UNITED- STATES PATENT OFFICE JOSEPH ERNST ELErcnEia, or DUDLEY, ENGLAND, AsSIeNoR oE-oNE-HALE TO THE BRITISH cAsT IRON RESEARCH ASSOCIATION, or BIBHINGHAI, ENGLAND CUPOLA ANDIJIKE FURNACE Original application filed May 19, 1930, Serial No. 453,777, and in Great Britain'llay 24, 1929. Divided and this application filed October 6, 1931.

This invention relates to the cupola furnaces employed for melting cast iron, steel, wrought iron or other metals, and in some cases slags, in which-air is admitted through tuyeres near the bottom of the furnace.

In particular the invention relates to cupolas in whichin addition to the mam -tuyeres situated adjacent to the melting 'zone,

partsof the cupola, and it has-been found impossible by regulation of both the main and supplementary tuyeres to obtaln the best control and distribution of the air required for the most efiicient operation of the cupola. The object of the present invention is to overcome this diiiiculty in a simple and con- The present invention comprises the use of main and supplementary tuyeres, and air regulating means actingon the main tuyeres on y plementary tuycres are used, of valves each containing an opening or passage through its interior. I

This apphcation is a division of my copending application,-Serial No. 453,777, filed May 19, 1930. i

In the accompanying sheet of explanatory drawings Figure 1 is a diagram (with one half in section) showing one means of carrying the invention into efiect.

Serial No. 567,226.

Figure 2 is a'diagram illustrating alter-.

native means.

.In carrying the inventin into eifect as 7 shown in Figure .1, the cupola a is surrounded by a wind chest 6. Adjacent to the lower part of the cupola and in direct communication with the wind chest are arranged a number of main tuyeres 0. Opposite the outer end of each tuyere is arranged a hollow spherical valve (1 by which the amount of air entering the tuyere can be conveniently regulated. The valve is formed with a screwed hollo'w stem 0 which passes through a screwed .plate 7' on the wind chest. The stem can be rotated by a handle 9. Apertures h, z, at the opposite ends of the stem enable the interior of the cupola to be inspected.

At convenient positions above the main tuyeres are arranged, preferably in direct communication with the wind chest, supplementary tuyeres j.

In the modification shown in Figure 2'the outer end of the main tuyerec is formed with a bend or elbow terminating in a horizontal annular seating 3 in the bottom ofthe wind chest 6. In con unction with this seating is arranged a ball valve 4 which can be raised or lowered by a rod 5 connected to a V lever 6. The latter is actuated by a. handle 7 and is secured by a rod 8 engagmg peg '0.

By means of the valves (1 or 4 the antity of air supplied through themaintuyeres'can be accurately adjusted .to suiir'the conditions obtaining in the furnace, and thereby excessiveoxidation of the metal is avoided and the quantity of solid fuel required is economized. By operating with a suitably restricted air supply at the main tuyeres the gas resulting from "the retraction in the melting zone may consistmainly of carbon monoxide, and this is consumed at a higher position in the furnace by air admitted through the supplemem' tary tuyeres. Preferably, when two or more 1 rows 0 supplementary tuyeres are used, the

tuyeres in any row alternate with those of the adjacent row or rows.

By this invention, wh ch consists essentially in effecting the air regulation by means of valves as above described actin on the main tuyeres only, an important a vantage is obtained, in that the relative proportions of air passing into the cupola through the main andsupplementary tuyeres are automatically varied. Both sets of tuyeres derive their air from the same wind chest. When the main tuyeres are fully open the greater part of the air enters the cupola through the main tuyeres. On restricting the air supply to the main tuyere, the amount supplied to the supplementary tuyres is automatically increased. Consequently on diminishing the air supply to the lower part of the cupola and thereby setting up a condition favourable to the production of carbon monoxide, the more air is admitted through the supple mentary tuyeres to the higher parts of the cupola where it is required to convert the carbon monoxide to carbon dioxide. By means-of valves as above described the desired regulation of the main air supply can be effected in a satisfactory manner at any time and while the cupola is in operation.

Vhen it is required to burn away slag deposits which have accumulated in the region.

of the main tuyeres the valves controlling the main tuyeres are closed completely.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is The process of operating a cupola or like furnace having a Wind chest and lowermain tuyeres and upper supplementary tuyeres in said wind chest, which comprises regulating the size of the openings in the main tuyeres to suit the condition of'the furnace and keeping wide open at all times the supplementary tuyeres, relying entirely on the automatic change ofpressure in the chest caused by the variation in the effective openings of the main tuyeres to regulate the amount of air passing through the supplementary tuyeres.

In testimony whereof I have signed my name to this specification. I

JOSEPH ERNST FLETCHER. 

